U.S. patent number 6,711,417 [Application Number 09/639,720] was granted by the patent office on 2004-03-23 for interface using an ish and a service manager.
This patent grant is currently assigned to Sprint Spectrum, L.P.. Invention is credited to Bryan Gorman, David A. Rush, Robert Wiese.
United States Patent |
6,711,417 |
Gorman , et al. |
March 23, 2004 |
Interface using an ISH and a service manager
Abstract
An interface between a public switched telephone network (PSTN),
a wireless communication network having a plurality of cells and a
plurality of mobile switching centers (MSCs), and a wireless
device. The interface includes a broadband telecommunications
network. It also includes an integrated services hub (ISH). The ISH
is communicatively coupled to the wireless device and the broadband
network. The ISH receives RF communications from the wireless
device and converts the RF communications into control and data
signals usable by said broadband network. The ISH has an antenna
with a first coverage area extending over a pico cell. The
interface also comprises a service manager communicatively coupled
to the broadband network, to the wireless network, and to the PSTN.
The service manager receives the control and data signals from the
ISH via the broadband network and forms and provides signaling
communications in response to receiving the control and data
signals. The signaling communications control the operation of
switches in the PSTN. The service manager communicates with
selected ones of the plurality of MSCs in the wireless network to
perform hand-offs of the wireless device from the first coverage
area to a selected one of the plurality of cells within the
wireless network.
Inventors: |
Gorman; Bryan (Mission, KS),
Rush; David A. (Merriam, KS), Wiese; Robert (Liberty,
MO) |
Assignee: |
Sprint Spectrum, L.P. (Overland
Park, KS)
|
Family
ID: |
31978961 |
Appl.
No.: |
09/639,720 |
Filed: |
August 16, 2000 |
Current U.S.
Class: |
455/550.1;
455/556.1; 455/560; 370/395.52 |
Current CPC
Class: |
H04W
92/06 (20130101); H04W 36/12 (20130101); H04W
84/18 (20130101); H04W 36/08 (20130101) |
Current International
Class: |
H04Q
7/22 (20060101); H04L 12/56 (20060101); H04Q
7/38 (20060101); H04B 001/034 () |
Field of
Search: |
;455/436,414,456,437,438,439,444,446,445,560,550,553.1,554.1,554.2,554.3,556.1,561
;370/395.5,395.51,395.52,395.53,395.6,395.61,218,352,353 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Bellcore, "Service Manager (SM) 1.0: ISUP Interface",
BD-SM-ISUP-INT-1, Issue 1.1, Jan. 1999, pp. 1-210. .
IS-41 Revision C Explained, "Basic Intersystem Handoff Functions",
pp. 135-160..
|
Primary Examiner: Tran; Congvan
Claims
We claim:
1. An interface between a public switched telephone network (PSTN),
a wireless communication network, and a wireless device, said
wireless communication network having a plurality of cells and a
plurality of mobile switching centers (MSCs), each of said
plurality of cells having a coverage area, said interface
comprising: a broadband packet network; an integrated services hub
(ISH), said ISH communicatively coupled to said wireless device and
said broadband packet network, said ISH receiving RF signaling and
media information from said wireless device and converting said RF
signaling and media information into control and media packets
usable by said broadband packet network, said ISH transmitting said
control and media packets over said broadband packet network, said
ISH having an antenna with a first coverage area extending over a
pico cell; and a service manager communicatively coupled to said
broadband packet network, to said wireless network, and to said
PSTN, said service manager receiving said control packets from said
ISH via said broadband packet network and forming and providing
signaling communications in response to receiving said control
packets, said signaling communications controlling the operation of
switches in said PSTN, said service manager communicating with
selected ones of said plurality of MSCs in said wireless network to
perform hand-offs of said wireless device from said first coverage
area to a selected one of said plurality of cells within said
wireless network.
2. The interface of claim 1 wherein said hand-offs are performed
using the IS-41 protocol.
3. The interface of claim 1 wherein said signaling communications
utilize the SS-7 protocol.
4. The interface of claim 1 wherein said broadband packet network
is coupled to a gateway, said gateway being further coupled to said
PSTN and said wireless network.
5. The interface of claim 1 further comprising a plurality of ISHs,
said plurality of ISHs being coupled to said broadband packet
network.
6. The interface of claim 4, wherein said ISH transmits said media
packets to said gateway via said broadband packet network.
7. The interface of claim 1, wherein said media information
includes voice information.
8. A method for interfacing a wireless device, a wireless network
having a plurality cells and a plurality of mobile switching
centers (MSCs), each of said cells having a coverage area, and a
public switched telephone network (PSTN), wherein said wireless
device is positioned within a pico cell, said pico cell having a
coverage area, the method of interfacing comprising the steps of:
receiving wireless communication signals representative of
communications from said wireless device; converting said wireless
communication signals into control signals and media information,
said media information including voice information; transmitting
said control signals and media information in a packet format over
a broadband packet network; using said control signals to route
said media information sequentially through said broadband packet
network to said PSTN; converting said control signals to signaling
communications; using said signaling communications to route said
media information through said PSTN and said wireless network; and
performing hand-offs of said wireless device from said pico cell to
a selected one of said plurality of coverage areas within said
wireless network and vice versa.
9. The method of claim 8 wherein said step of performing hand-offs
utilizes the IS-41 protocol.
10. The method of claim 8 wherein said signaling communications
conform to the SS-7 protocol.
11. A computer readable medium having stored therein instructions
for causing a processing unit to execute the method of claim 8.
12. The method of claim 8, further comprising: making a hand-off
measurement to determine whether a hand-off from said pico cell to
a selected one of said plurality of coverage areas within said
wireless network is appropriate.
13. The method of claim 12, further comprising: selecting a
candidate MSC for said hand-off from said pico cell.
14. An interface between a wireless device, a wireless network, and
a public switched telephone network, wherein said wireless device
is positioned in a pico cell, said pico cell having a coverage
area, wherein said wireless network has a plurality of coverage
areas, said interface comprising: means for receiving wireless
communication signals representative of communications from said
wireless device; means for converting said wireless communication
signals into control signals and media information, said media
information including voice information. and for transmitting said
control signals and media information in a packet over a broadband
packet network; means for using said control signals to route said
media information sequentially through said broadband packet
network to said PSTN; means for converting said control signals to
signaling communications; and means for using said signaling
communications to route said media information through said PSTN
and said wireless network.
15. The interface of claim 14 further comprising means for
performing hand-offs of said wireless device from said pico cell to
a selected one of said plurality of coverage areas within said
wireless network and vice versa.
16. The interface of claim 15 wherein said means for performing
hand-offs utilizes the IS-41 protocol.
17. An interface between a public switched telephone network
(PSTN), a wireless communications network, and a wireless device,
wherein said wireless communication network has a plurality of
cells and a plurality of mobile switching centers (MSCs), each of
said cells having a coverage area, said interface utilizing a
broadband packet network and comprising: an integrated services hub
(ISH), said ISH communicatively coupled to said wireless device and
said broadband packet network, said ISH receiving RF signaling and
media information from said wireless device and converting said RF
signaling and media information into control and media packets
usable by said broadband packet network, said ISH transmitting said
control and media packets over said broadband packet network, said
ISH having an antenna with a first coverage area extending over a
pico cell; and a service manager communicatively coupled to said
broadband packet network, to said wireless network, and to said
PSTN, said service manager receiving said control packets from said
ISH via said broadband packet network and forming and providing
signaling communications in response to receiving said control
packets, said signaling communications controlling the operation of
switches in said PSTN.
18. The interface of claim 17, wherein said media information
includes voice information.
19. A system for interfacing between a pico cell, a wireless
network and a public switched telephone network, wherein said pico
cell has an associated wireless device, and said wireless network
includes a plurality of cells, said system comprising: means for
receiving control signals and media signals, said control signals
and media signals being representative of communications from said
wireless device; means for converting said control signals into
signaling communications; means for using said control signals to
route said media signals in a packet format through a broadband
packet network; and means for handing-off calls from a selected one
of said cells in said wireless network to said pico cell.
20. The system of claim 19, wherein said media signals include
voice signals.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to wireless networks. More
particularly, the invention relates to interfaces between networks
that use an integrated services hub (ISH).
2. Description of Related Art
A variety of different types of networks exist in today's
telecommunication environment. For example, a wireless
telecommunication network represents one type of network. In
wireless networks, switching is performed by mobile switching
centers (MSCs). Each MSC typically controls one or more base
stations or base transceiver stations (BTSs), sometimes via one or
more base station controllers (BSCs). Each BTS provides a wireless
coverage area, within which mobile stations can communicate with
wireless devices over an air interface. The wireless devices can be
cellular or PCS telephones, or other devices. Different formats may
be used for communicating over the air interface. The most commonly
used formats in the United States are AMPS, TDMA, and CDMA.
Each wireless device typically has a "home" wireless network, in
which a home location register (HLR) serves as a centralized
repository of information about the wireless device. Typically, the
HLR contains a service profile for the wireless device, the last
reported location of the wireless device, and the current status of
the wireless device, such as whether it is inactive, active, or
busy. The service profile indicates the services to which the
wireless device subscribes. Typically, the HLR also has access to
the service logic needed to provide the subscribed services.
When an MSC needs to find information about a wireless device, such
as where the wireless device is located or the services to which
the wireless device subscribes, the MSC queries the HLR
corresponding to that wireless device. Thus, to inquire about a
wireless device that is roaming, i.e., operating on a network other
than its home network, the MSC queries an HLR that is outside of
its network. Typically, an MSC determines the proper HLR to query
based on the mobile identification number (MfN) transmitted by the
wireless device.
Broadband packet networks represent another type of network. For
example asynchronous transfer mode (ATM) networks have been
developed to provide broadband transport and switching capability
to Local Area Networks (LANs) and Wide Area Networks (WANs). Frame
relay networks are another type of broadband packet network. Other
types of broadband packet networks are possible as well.
For example, the Sprint Integrated On-Demand Network (ION) is a
broadband network that is able to deliver a variety of services,
such as voice, data, and video, to an end user at a residential or
business location. The Sprint ION has a wide-area IP/ATM or ATM
backbone that is connected to a plurality of local loops via
multiplexers. Each local loop carries ATM over ADSL (Asymmetric
Digital Subscriber Line) traffic to a plurality of Integrated
Services Hubs (ISHs), which may be at either residential or
business locations. Currently, ISHs do not provide wireless
service.
The public switched telecommunications network (PSTN) is still
another type of network. The PSTN includes switches, which can
route both voice and data communications between end users.
Typically, these switches are Class 5 switches.
Different types of networks are often connected to each other. For
example, wireless networks can be connected to broadband networks.
Both can be connected to the PSTN. There is a need to interconnect
these different types of networks such that devices in one network
can communicate with devices in other networks. A need exists to
allow a wireless device (e.g., a PCS handset) to work as an on-net
terminal device on a broadband network (e.g., the Sprint ION). It
would also be desirable to provide wireless service to devices
using an existing ISH. If a wireless coverage area is provided for
an existing ISH, there is an additional need to hand-off calls as
devices move from the small coverage area (of the ISH) to coverage
areas of other wireless networks (and vice versa).
SUMMARY OF THE INVENTION
The present invention allows for a small wireless coverage area
using an existing integrated services hub (ISH). The ISH may be
connected to a service manager. Together, the ISH and service
manager provide an interface, by which wireless devices coupled
(via an air interface) to the ISH can communicate with devices in
other networks.
In one embodiment of the present invention, the ISH provides a
wireless coverage area, in which a user can employ a standard
wireless telephone, such as a Sprint PCS telephone, to communicate
with the ISH over an air interface. The ISH includes an antenna, an
RF transceiver, vocoders, and other components to provide the ISH
with the functionality of a CDMA base station controller (BSC). The
ISH converts communications received from the wireless device into
control and data signals having a format that is compatible for
transmission on a broadband network.
Typically, the wireless coverage area provided by the ISH will be
sufficient to include the home and yard area for a residential
customer and the office area for a business customer but will not
extend very far beyond these areas. Thus, the wireless coverage
area may be termed a "pico-cell" or "EndoCell."
In an exemplary embodiment, the ISH is coupled to a broadband
network. The broadband network is, in turn, coupled to a service
manager, to a wireless network, and to the PSTN. The service
manager is then coupled to both the wireless network and the
PSTN.
The service manager receives control and data signals, via the
broadband network, from the ISH and translates these signals into
signaling communications, for example, SS-7 and IS-41 control
signals. The SS-7 control signals are used to route communications
through the PSTN. The IS-41 signals are used to perform hand-offs
of wireless devices from the pico-cell to cells in the wireless
network and vice versa.
In this way, an ISH provides a small wireless coverage area (the
pico-cell). In addition, the service manager and ISH provide an
interface between devices in the small coverage area and devices
coupled to other networks. Finally, the ability of the service
manager to provide hand-offs between the pico-cell and other cells
in other networks allows a customer's wireless telephone to be used
as both a home telephone and a mobile telephone for traveling.
These as well as other features and advantages of the present
invention will become apparent to those of ordinary skill in the
art by reading the following detailed description, with appropriate
reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Exemplary embodiments of the present invention are described herein
with reference to the drawings, in which:
FIG. 1 is block diagram showing a plurality of interconnected
networks using the integrated services hub (ISH) and service
manager, in which an exemplary embodiment of the present invention
can be implemented;
FIG. 2 is a block diagram of the integrated services hub (ISH) in
accordance with an exemplary embodiment of the present
invention;
FIG. 3 is a block diagram of the integrated services hub (ISH) in
accordance with an exemplary embodiment of the present
invention;
FIG. 4 is a block diagram of the service manager in accordance with
an exemplary embodiment of the present invention;
FIG. 5 is a flowchart illustrating the hand-off process in
accordance with an exemplary embodiment of the present
invention;
FIG. 6 is a block diagram showing the hand-off forward process in
accordance with an exemplary embodiment of the present invention;
and
FIG. 7 is a block diagram showing the hand-off back process in
accordance with an exemplary embodiment of the present
invention.
DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT
Referring now to FIG. 1, a block diagram showing a plurality of
interconnected networks using the integrated services hub (ISH) and
service manager is shown. A user device 100 is coupled to an
integrated services hub (ISH) 108. The coupling is via a signaling
channel 104 and a media channel 106. The signaling channel 104 and
the media channel 106 are over an air interface. The user device
100 and ISH 108 are located in a cell 102.
The user device 100 can be any type of personal communication
device that provides voice and/or data services to the user of the
device. For example, the user device may be a Sprint PCS handset.
However, the user device 100 can also be any device that a user
accesses to input or retrieve voice messages or data, such as a
personal computer or a hands-free speaker phone. If the user device
100 is a personal computer, the personal computer may be coupled to
a data interface. The data interface may then be coupled to the
ISH. Other examples of user devices and other connections and
arrangements are possible.
The cell 102 is a cell used in, for example, a CDMA cellular phone
system. Preferably, the wireless coverage area provided by the ISH
will be sufficient to include the home and yard area for a
residential customer and the office area for a business customer,
but will not extend very far beyond these areas. Thus, the wireless
coverage area may be termed a "pico-cell" or "EndoCell." Although
shown as a smooth curve, the boundaries of the cell 102 may be
irregular and overlap with the coverage areas of other cells. The
coverage area of the cell 102 may be substantially outside the
coverage area of the cells of other wireless networks.
Alternatively, the coverage area of the cell 102 may be within the
coverage area of cells of other wireless networks.
The ISH 108 receives signaling information over signaling channel
104 and voice signals over the media channel 106. Alternatively,
the signaling information and voice signals may be over the same
channel. The media channel 106 may also be used to transmit
computer data, voice data, or video data. Other types data can be
transmitted over the media channel, as well.
After receiving the signals, the ISH converts the signaling
information and the voice signals into control and data signals.
The control and data signals are in a format suitable for
transmission over a broadband packet network 110. For example, the
control and data signals may be in the form of ATM or IP
packets.
The ISH 108 is coupled to a service manager 112 via a signaling
link 114. The coupling is accomplished through the broadband packet
network 110. The ISH 108 is coupled to a gateway 120 (also through
the broadband packet network 110) via a media link 116. The service
manager 112 is coupled to the gateway 120 by a signaling link
118.
The service manager 112 is coupled to a signaling and hand-off
network 121 via signaling link 123. A second ISH 111 is coupled to
the broadband network 110 via links 114 and 116. A second user
device 113 is coupled to the second ISH 111. The user device 113
can be any type of device that allows a user to enter or retrieve
data or voice messages, for instance.
The signaling and hand-off network 121 is coupled to a PSTN 122 via
a signaling link 125 and to a wireless network 132 via a link 130.
The gateway 120 is also coupled to the wireless network 132 via a
communication link 124 and to the PSTN 122 by a communication link
127. A third user device 128 is coupled to the PSTN 122 via a
communication link 126. The user device 128 can be any type of
communication device including a telephone or computer. Other types
of user devices are possible.
The wireless network 132 is any type of wireless network capable of
communicating with a plurality of wireless devices. The wireless
network 132 will typically be organized into a plurality of cells.
The wireless network 132 comprises base stations, mobile switching
centers (MSCs), and databases that contain information relating to
the wireless devices in the wireless network such as the telephone
numbers of these devices.
The service manager 112 issues signaling communications that
control switches in the PSTN 122. The signaling communications
manipulate these switches, which route voice information through
the network. The service manager 112 uses a signaling protocol, for
example, Signaling System 7, for this purpose.
SS-7 is a global standard for telecommunications defined by the
International Telecommunications Union (ITU) Telecommunication
Standardization Sector (ITU-T). The standard defines the procedures
and protocols, by which network elements exchange information to
effect wireless and wireline setup, routing, and control. In
addition, variants of SS-7 exist such as those defined by the
American National Standards Institute (ANSI), Bell Communications
Research (Bellcore), and the European Telecommunications Standards
Institute (ETSI). Of course, the signaling used in this invention
is not limited to SS-7 or any particular type; the specific type of
signaling used will depend on the exact nature and characteristics
of the network and the applications desired.
The content of the signaling communications may include flags,
length indicators, information fields, and check bits. Of course,
the signaling communications may contain other information, as
well. The signaling communications are used for call establishment
and release. For example, when a call is to be routed from the
broadband network to the PSTN, an initial address message (IAM) is
formulated and sent from the service manager to a switching office
in the PSTN. The IAM indicates the circuit used to transmit the
call to the PSTN.
The service manager 112 also issues other signaling communications
that are used by the wireless network 132, for example, signaling
communications complying with the IS-41 specification. The IS-41
specification is used in wireless networks to provide services such
as roaming, authentication, and hand-offs. Specifically, the
intersystem hand-off function of IS-41.2-C, IS-41.5-C, IS.41.6-C of
ANSSI/TIA/EIA-41 may be used, all of which are incorporated herein
by reference. Of course, other specifications can be used in place
of the IS-41 specification.
Specifically, the service manager 112 appears to the MSCs in the
wireless network to be another MSC in the wireless network. The MSC
uses existing databases in the wireless network 132 to make
connections to the wireless device 100. A service profile for the
wireless device 100 is placed in the databases of the wireless
network 132. Thus, an MSC in the wireless network can communicate
with a wireless device in the cell 102.
The management of the service profile may be distributed between
the service manager 112 and MSCs in the wireless network 132. In
other words, either the MSC or the service manager may place the
service profile of the wireless device 100 in the databases of the
wireless network 132. In addition, the service profile may be
managed centrally by a dedicated server that is accessed via the
signaling network.
When the user device 100 moves from the small coverage area of the
ISH to a cell within the wireless network 132 (or vice versa), a
hand-off occurs between the cell 102 and the cell within the
wireless network 132. The service manager 112 negotiates with the
MSCs in the wireless network 132 during hand-offs involving the
user device 100. The negotiations decide whether and when a
hand-off is needed. In addition, the negotiations exchange signal
strength and frequency information, and all other types of
information needed to complete a successful hand-off between
cells.
Another function of the service manager 112 is to set up and
control calls (placed at any user device) through the broadband
network 110. For example, the service manager routes these calls
from device 113, to ISH 111, to ISH 108, and to user device 100.
Similarly, the service manager 112 may route these calls from user
device 113 to ISH 111, to gateway 120, to either PSTN 22, or to
user device 128. Of course, the service manager 112 may route these
calls from user device 100 to user device 113 and user device 128
to user device 113. Other routings are possible.
The broadband packet network 110 is a packet network, for example,
an ATM network such as the Sprint ION. Another example of a
broadband network is an IP network. Other examples of broadband
networks are possible. The broadband packet network 110 may
comprise a series of switches. The broadband packet network 110
contains the functionality to route both voice signals and
signaling/data through the network 110.
The PSTN 122 also comprises a series of switches. Illustratively,
the PSTN 122 comprises Class 5 switches and is a TDM network.
However, the PSTN 122 may comprise other types of switches and use
other transmission technologies. Alternatively, the PSTN 122, which
transmits voice messages, can be replaced by a network that
transmits data, for example, the Internet.
The signaling and hand-off network 121 includes service control
point (SCPs) and service transfer points (STPs). One purpose of the
signaling and hand-off network 121 is to route signaling
communications to the PSTN 122 and the wireless network 132.
One example of the operation of the interconnected networks and
interface of FIG. 1 is as follows. A call is placed from the user
device 100. The user device 100 transmits both signaling
information (over the signaling channel 104) and media information
(over the media channel 106). The signaling and media information
is transmitted to the ISH 108. The ISH 108 converts this signaling
information into control packets, which are transmitted over the
broadband network 110 to the service manager 112 via the signaling
link 114.
The ISH also converts the media information into media packets and
transmits these media packets over the link 116 to the gateway 120.
The gateway 120 transmits the media packets to the wireless network
132 or the PSTN 122 (depending upon the final destination of the
call).
The service manager 112 may form signaling communications (e.g.,
using SS-7), which route the media packets input by the gateway
through the wireless network 132 or the PSTN 122. For example, the
signaling communications may route the media packets through the
PSTN to the user device 126. Additionally, the service manager 112
may also form other signaling communications (e.g., using IS-41)
and negotiate hand-offs between the cell 102 and cells within the
wireless network 132 as the user device moves from cells within the
wireless network 132 and the pico-cell 102.
Thus, the service manager 112 and ISH 108 cooperatively provide an
interface between wireless devices residing in the pico-cell 102
and devices within cells of the wireless network 132. The option of
communication with other networks, such as the PSTN, is also
provided. The ability of the service manager 112 to negotiate with
MSCs in the wireless network 132 allows hand-offs to occur between
the pico-cell 102 and cells in the wireless network 132.
Referring now to FIG. 2, a block diagram of the ISH is shown. A
cellular telephone 200 is coupled via an air interface to an
antenna 202. The cellular telephone 200 transmits voice and
signaling information to the antenna 202 over a voice channel and a
signaling channel. Alternatively, the voice and signaling
information may be over the same channel.
The cellular telephone 202 is located within a cell 204. The area
of the cell 204 represents the coverage area of the antenna 202.
Illustratively, the cell 204 is an endocell or pico-cell that has a
coverage area extending over a small geographical area, for
example, over a house.
An integrated services hub (ISH) 206 comprises the antenna 202, an
RF module 212, a conversion module 210, a voice and data bus 208, a
translation module 214, and an ADSL module 216. The antenna is
coupled to the RF module 212. The RF module 212 is coupled to the
conversion module 210. The conversion module 210 is coupled to the
voice and data bus 208. The voice and data bus 208 is coupled to
the translation module 214. Finally, the translation module 214 is
coupled to the ADSL module 216.
The RF module 212 comprises an RF receiver, which receives voice
and signaling information over the voice and signaling channel. The
RF receiver is tuned to receive RF signals within a certain
frequency bandwidth. For example, the RF receiver may be tuned to
receive signals in the 1900 MHz bandwidth.
The conversion module 210 converts the information transmitted over
the voice channel and signaling channel (received from the RF
module) into separate information streams, which can be processed
later. For example, the conversion module 210 separates
communications received over the voice channel and the signaling
channel into a PCM voice stream and a signaling/data stream,
respectively.
The voice and data bus 208 is an internal bus, which couples the
conversion module 210 to the translation module 214. The voice and
data bus 208 transmits the voice and signaling streams formed in
the conversion module 210.
The translation module 214 translates the voice stream and the data
stream received over the bus 208 into ATM cells. For example, the
translation module 214 may encapsulate the voice stream received
over the voice and data bus 208 into AAL-2 cells. The translation
module may also translate the signaling stream received from the
voice and data bus 208 into SGCP (over AAL-5) cells.
The ADSL module 216 provides asymmetrical digital subscriber line
(ADSL) connection to the broadband packet network. The ADSL module
216 provides highspeed access to the broadband network.
The cellular telephone 200 communicates through the CDMA network to
the ISH 206. The cellular telephone 200 transmits voice and
signaling information to the ISH 206. The ISH 206 converts
(translates) the voice and signaling information received from the
cellular telephone 200 into signals useable by the packet network
218, for example, into packets. The packets are transmitted by a
service manager to other networks, such as wireless networks and
the PSTN.
Referring now to FIG. 3, a block diagram of another embodiment of
the ISH is shown. A cellular phone 300 is coupled over an air
interface to an integrated services hub (ISH) 318. The coupling is
accomplished via an antenna 302 and an air interface. The cellular
phone 300 transmits voice and signaling information to the antenna
302 via a voice channel and a signaling channel. Alternatively, a
single channel may be used.
The ISH comprises the antenna 302, RF module 306, PCS CDMA module
308, bus 310, interface module 312 and ADSL module 314. The antenna
is coupled to the RF module 306. The RF module 306 is coupled to
the PCS CDMA module 308. The PCS CDMA module 308 is coupled to the
bus 310. The bus 310 includes a Codec transcoder 311a and a
signaling and data channel 311b.
The bus is coupled to the interface module 312. The interface
module comprises an SGCP/AAL-5 module 313a and an AAL-2 module
313b. Specifically, the transcoder 311a is coupled to the AAL-2
module 313b and the signaling and data channel 311b is coupled to
the SGCP/AAL-5 module 313a. The interface module 312 is coupled to
the ADSL module 314.
The cellular phone 300 is any type of cellular telephone such as a
Sprint PCS handset. Alternatively, other types of wireless devices,
such as pagers or computers (having wireless access), may be
used.
The RF module 306 comprises a RF receiver, which receives
information over the voice channel and the signaling channel. The
RF receiver is tuned to receive RF signals within a certain
frequency bandwidth. For example, the RF receiver may be tuned to
receive signals in the 1900 MHz bandwidth.
The PCS CDMA module 308 converts the information transmitted over
the voice channel and signaling channel (and received from the RF
module) into a PCM voice stream and a signaling stream. The PCS
CDMA module comprises a codec, which converts voice signals from
the RF module 306 into digital bit streams. The codec also performs
the reverse function. In one example, the codec may be as IS-127
codec.
The transcoder 311a translates voice bits streams from the format
of the PCS CDMA module 308 (e.g., IS-127) into the format of the
AAL-2 module 312 (e.g., G.711). The transcoder 311a also provides
the reverse functionality. The signaling channel 311b transmits
signaling information to the SGCP/AAL-5 module 313a and vice
versa.
The SGCP/AAL-5 module 313a converts the signaling information
received over the signaling channel 311b into AAL-5 cells. The
AAL-2 module 313b converts the PCM voice information received over
the PCM voice channel 311a into AAL-2 cells. The AAL-2 module 313b
includes a codec, which converts analog signals from the ADSL
module 314 into a digital bit stream. The codec also performs the
reverse function. In one example, the codec is a G.711 codec.
The ADSL module 314a provides asymmetrical digital subscriber line
(ADSL) connection to the network, which is a high-speed connection.
The ADSL module is connected to a broadband packet network 316.
The broadband packet network 316 can be the Sprint ION. The Sprint
ION also includes gateways for connecting to other networks. In
particular, the Sprint ION includes trunk gateways for connecting
to circuit-switched pathways in the PSTN, signaling gateways to
wireless networks, and signaling gateways to connect to the
Internet.
Referring now to FIG. 4, the operation of the service manager is
now described. A service manager 400 includes an SGCP call agent
402, an IS-41 interface 408, and an SS-7 interface 410. The SGCP
call agent 402 is coupled to the IS-41 interface 408 and to the
SS-7 interface 410.
The IS-41 interface 408 is coupled to a hand-off network 407a. The
hand-off network 407a is coupled to an IS-41 interface 420. The
SS-7 interface 410 is coupled to a signaling network 407b. The
signaling network 407b is coupled to an SS-7 interface 422 in an
MSC 412. The MSC 412 is in a wireless network 432. The signaling
network 407b is also coupled to an SS-7 interface 428 in the PSTN
428.
An ISH 414 resides within a pico-cell 411. The ISH is coupled to a
broadband network 418. The coupling is via a voice channel 405a and
a signaling channel 405b. A second ISH 403 is also coupled to the
broadband network 418. The coupling is via a voice channel 409a and
a signaling channel 409b. The broadband network 418 is coupled to
the SGCP call agent 402 (with the service manager 400). The
broadband network is also coupled to a gateway 416 via a signaling
channel 417a and a voice channel 417b. The gateway 416 transmits
voice information over bearer channels 424 (within the MSC 412),
over bearer channels 430 (within the MSC 430), and is also coupled
to the SGCP call agent 402. The bearer channels shown in FIG. 4 are
virtual connections rather than physical connections.
The broadband network 418 may include routers and switches (not
shown). The routers and switches receive packets of information
with IP addresses and route the packets (using the IP address) to
the appropriate destination. For example, if a first ISH attempts
to dial a second ISH, the destination address will be the address
of the second ISH.
The ISH transmits SGCP control signals to the SGCP control agent
402 via the broadband network 418. The ISH also transmits voice
information to the broadband network 418. The voice information is
routed by the broadband network 418 to the appropriate destination.
The destination may be the second ISH, the PSTN, or the wireless
network. If the destination is the PSTN 428 or the wireless
network, then the voice information passes through the gateway.
The SGCP control signals are in the form of packets, for example,
IP packets. The SGCP call agent 402 converts the SGCP control
signals from the SGCP format into formats compatible with the SS-7
and IS-41 specifications. These converted signals are transmitted
to the IS-41 interface 408 and the SS-7 interface 410. The IS-41
interface 408 and SS-7 interface 410 create signaling
communications consistent with the IS-41 and SS-7 specifications,
which are transmitted to the wireless network 432 and the PSTN 426
via the hand-off network 407a and the signaling network 407b.
The SGCP call agent 402 also transmits signaling information to the
gateway 416. For example, the call agent 402 may signal the gateway
to produce dial tone and or the call agent may send digit
information to the gateway 416. The gateway 416 passes voice
information to the wireless network 432 and the PSTN 428 via the
bearer channels 424 and 430, respectively.
The IS-41 interface 420 in the MSC 412 coordinates hand-offs
between wireless devices moving between cells in the wireless
network 432 and the cell 411. The interface 420 negotiates with the
service manager 400 to decide whether and when a hand-off is
needed. In addition, the service manager 400 and MSC 412 exchange
signal strength and frequency information, and all other types of
information needed to complete a successful hand-off between the
cell 411 and cells within the wireless network 432.
The SS-7 interfaces 422 and 428 receive signaling communications
from the service manager 400. The SS-7 interface 422 takes the
signaling communications from the service manager and uses these
communications to route voice information over bearer channel 424
through the wireless network. Similarly, the SS-7 interface 428
uses these communications to route voice information over the
bearer channel 430 through the PSTN 426. The bearer channels 424
and 430 transport data or voice information across the wireless
network 432 and 426, respectively.
The IS-41 interface 408 provides signaling communications to the
wireless network 432 in the form of IS-41 signals. The SS-7
interface 410 provides signaling communications to the signaling
network 412.
Referring now to FIG. 5, the hand-off interface between a service
manager and an MSC is described. Either the MSC or the service
manager can perform the following functions.
At step 502, hand-off measurements are made by the serving MSC (or
service manager). Hand-off measurements determine whether a
hand-off is appropriate. In addition, the measurements identify
particular MSCs or service managers ("the candidate MSCs"), which
should be considered for the hand-off. Further, the measurements
evaluate all candidate MSCs (or service managers) to see if each
candidate MSC (or service manager) is suitable to accept the
call.
At step 504, a candidate MSC (or service manager) is selected.
Next, at step 506, the form of the hand-off is determined. If the
candidate MSC (or service manager) is already involved in the call
and connected to the serving MSC (or service manager) via an
inter-MSC circuit, a hand-off back is used. Otherwise, a hand-off
forward or path minimization may be attempted. At step 508, the
hand-off is performed. Execution then ends.
Referring now to FIG. 6, one example of the hand-off forward
process between an MSC and a service manager is described. A phone
601 is coupled to PSTN 604. PSTN 604 is coupled to an MSC 606. The
MSC 606 is coupled to a base station 602. The base station 602 is
coupled via an air interface to a mobile device 608. The mobile
device 608 is moving between a cell 603 and a pico-cell 605. The
mobile device 608 is coupled via an air interface to an ISH 610,
which is in the pico-cell 605. The ISH 610 is coupled to a service
manager 612 via a broadband network (not shown). An inter-MSC
circuit couples the MSC 606 to the service manager 612. In this
example, it is assumed that a connection between the phone 601 and
mobile device 608 is desired. It is also assumed that a hand-off
measurement process has determined that a hand-off forward should
occur between the MSC 606 and the service manager 612.
The MSC 606 issues a request 620 for a hand-off forward to the
service manager 612. The service manager 612 issues an acceptance
622 to the MSC 606. The inter-MSC circuit is now ready for the
hand-off. The MSC issues a hand-off order 614 to the mobile device
608. The mobile device 608 tunes to the new channel 616. The
service manager issues a detection response 624 to indicate to the
MSC 606 that the mobile has been detected by the service manager
612. The service manager 612 connects the call path from the MSC
606 (over the inter-MSC circuit 618) to the service manager
612.
Referring now to FIG. 7, one example of the hand-off back process
between an MSC and the service manager is described.
A phone 701 is coupled to PSTN 704. PSTN 704 is coupled to an MSC
706. The MSC 706 is coupled to a base station 702. The base station
702 is coupled via an air interface to a mobile device 708. The
mobile device 708 is moving between a cell 703 and a pico-cell 705.
The mobile device 708 is coupled via an air interface to an ISH
710, which is located in the pico-cell 705. The ISH is coupled to
the service manager via a broadband network (not shown). An
inter-MSC circuit couples the MSC 706 to the service manager 712.
In this example, it is assumed that a connection between the phone
701 and mobile device 708 is desired. It is also assumed that a
hand-off measurement process has determined that a hand-off back
should occur between the service manager 712 and the MSC 706.
The service manager 712 issues a handback request 720 for a
hand-off back to the MSC 706. The MSC 706 issues an acceptance 722
to the service manager 712. The service manager 712 issues a
hand-off order 716 to the mobile device 708. The mobile device 708
tunes to the new channel 714. The MSC 706 issues a release request
724 to the service manager 712, which requests the release of the
unnecessary inter-MSC circuit 718. The service manager issues a
release acknowledgement 726 and the inter-MSC circuit is released
and can be used for other hand-offs.
It will be realized that the hand-off processes described in
relation to FIGS. 6 and 7 are for illustrative purposes only. Other
hand-off processes with different message flows are possible.
As in most telecommunications applications, those skilled in the
art will appreciate that many of the elements described herein are
functional entities that may be implemented as discrete components,
in any suitable combination and location. Further, various
functions described herein as being performed by one or more
entities may be carried out by a processor executing an appropriate
set of machine language instructions stored in memory. Provided
with the present disclosure, those skilled in the art can readily
prepare appropriate computer instructions to perform such
functions.
Exemplary embodiments of the present invention have been
illustrated and described. It will be understood, however, that
changes and modifications may be made to the invention without
deviating from the spirit and scope of the invention, as defined by
the following claims.
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